A conventional configuration for a metal demolition shears 900 as known in the prior art is illustrated in FIGS. 1 and 2. The shears 900 are configured to be attached to the boom structure of, for example, excavating or earth-moving excavation equipment such as that made by Caterpillar, Komatsu, Hitachi, Kobelco, etc. The shears 900 include a lower, fixed or stationary jaw 902 and an upper, movable jaw 904. The upper, movable jaw 904 is pivotally mounted by means of pivot structure 906, which includes, for example, a main shaft, tie rod, rotation bearings and thrust bearing, end caps, and fasteners so as to pivot relative to the lower fixed or stationary jaw 902, as illustrated by double-headed arrow 908. Piston member 910 articulates (drives) the upper, movable jaw 904 for such pivoting movement. The stationary jaw 902 is mounted into a stick weldment structure 912 that supports the piston member 910 and the pivoting upper jaw 904, and the stick weldment structure 912 is mated to the boom of the machinery by means of a fixed mounting bracket 913 (FIG. 1) or a rotational mounting adapter 914 (shown in FIG. 2) and rotational drive system (not shown in FIG. 1).
The lower, fixed jaw 902 includes a fixed blade member 916 and a guide member 920. The guide blade member 920 is laterally spaced from the fixed blade member 916 and extends generally parallel to the fixed blade member 916. A cross-member 922 extends between and is connected to the endmost portions of the fixed blade member 916 and the guide member 920. Together, the fixed blade member 916, guide member 920, and cross-member 922 define a slot 924 into which the upper, movable jaw 904 moves during operation of the shears 900.
The shears 900 includes a number of hardened metal inserts that provide various cutting, piercing, or load-supporting edges and surfaces. In particular, the lower, fixed jaw 902 has a pair of hardened steel blade insert members 926, and the upper, movable jaw 904 has a pair of hardened steel insert members 928. The blade insert members 926 and 928 fit within correspondingly configured recesses or seating surfaces formed in the lower and upper jaws 902 and 904, respectively, and are secured therein, e.g., by bolts. As the shears 900 is operated and the upper, movable jaw 904 is pivoted closed relative to the lower, fixed jaw 902, the blade insert members 928 in the upper, movable jaw 904 move past the blade insert members 926 in the lower, fixed jaw 902, and the cutting edges 930 and 932 of the lower and upper blade insert members 926, 928, respectively, co-act to shear or cut a workpiece such as I-beams, pipes, scrap sheet metal, etc. held between the jaws of the shears. As disclosed, for example, in U.S. Pat. No. 5,992,023, the blade insert members may be indexable, meaning that they can be reoriented and repositioned to present new or fresh cutting edges as the cutting edges 930, 932 become worn.
As the upper, movable jaw 904 pivots downward to shear a workpiece between the steel blade insert members 926 and 928, the workpiece tends to force the upper, movable jaw 904 laterally away from the fixed blade member 916 of the lower, fixed jaw 902. The guide member 920 limits or constrains such lateral deflection of the upper, movable jaw 904. As a result, as the movable jaw 904 pivots downward into the slot 924, the lateral surface 934 of the nose portion 936 of the movable jaw 904 bears against inner-facing surface 938 of the guide member 920. Therefore, a hardened steel wear plate 940 is customarily secured to the lateral surface 934 of the nose portion 936, and a hardened steel wear insert 942 is secured to the inner-facing surface 938 of the guide member 920.
In addition to the blade insert members 926, 928, wear plate 940, and wear insert 942, a shears 900 conventionally has a hardened steel piercing tip 944 that is secured, e.g., by welding to a lower surface of the nose portion 936 at a forwardmost portion thereof. A hardened steel cross blade insert 946 is secured within a correspondingly shaped recess in the cross member 922 and cooperates with and/or provides a cutting surface against which the piercing tip 944 engages when the shears 900 is being used to pierce holes through larger, generally flattened pieces of scrap metal.
Customarily, the various cutting, supporting, piercing, and/or wear elements described above (the blade insert members 926, 928, the wear plate 940, the wear insert 942, the piercing tip 944, and the cross blade insert 946) are provided as individual, separate components.